how do you seal old cast iron pipe

[ewan]

was at a call out today, a leak had brought cieling down in the flat below. after a bit of investigating and lifting lino,adhesive tiles, laminate flooring and floorboards I found leak was coming from an old lead waste that had been flattened and was connected to 3 inch cast iron. the basin connected in to bath which then teed in to the cast iron closer to the wall. this is at least 6 years old so i think a blockage has started water flowing back along the cast iron and out thru the old lead pipe. Anyway what i need to know is what is best way to permanently seal the end of cast iron pipe. I was thinking of cutting lead off at collar and then blocking up hole with cement.
advice appreciated cheers

 

[easyt]

Sounds a bit of a bodge job 😉.

If I was going to bodge it I would have cut the lead pip a good 9 inches from the collar. Made sure it was dry, and filled with silicone. I presume access is a problem. Can't you cut the lead pipe and use some kind of a stop end. I'm sure someone will have a better suggestion Ewan.

 

[justlead1]

Hi. I would consider why it leaked? Probably a blocked waste backing up and bad jointing. Capping the end of a lead pipe is not difficult. In this case bend the pipe in order to get is in a nice position. cut through the pile (wood saw) this will leave nice clean pipe end, push a tight wedge of paper down the end to stop any solder from dropping down pipe. Apply some flux and swipe a dome of solder over the end. If there is plenty of lead pipe there cut a bit of and practice in the back of the van.

 

[Bernie2]

Hmm!

The usual way is to take the lead waste out of the collar. Then caulk in either a cap end or cleaning eye ferrule.

 

[Whyme]

cut the lead flush or chisel it out of the inside of the cast and put a bung init, the expandable ones with a wing nut. you can get most sizes.

 

[AWheating]

fenco qwick cap may work

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[Leo21]

Would of thought mechanical coupler with proper plastic end cap/bung.

 

[stevetheplumber]

we used to sweat the brass thimble out bung with paper and cement them over but probably easier to cut the lead and wedge a macalpine cap on or you can get fernco rubber caps